Method and structure for reclosable containers

ABSTRACT

.Iadd.An elongate closed flexible integral plastic film tube for use in making reclosable bags with the tube having first and second interlocking rib elements and first and second groove elements on the surface thereof each shaped for cooperative pressure engagement and forcible separation between the ribs and grooves with the elements spaced apart from each other in both circumferential directions and the film at one side of the elements for forming the body of a bag formed from the tube and the film at the other side of the elements providing a flange forming portion. The elements are spaced so that the bag portion is wider than the flange portion. .Iaddend.

This invention relates to bags and tubes for manufacturing bags made ofsynthetic resin, wherein have been formed integral with the bag materialat the inner surface of the bag mouth vis-a-vis each other, a male riband a female rib which are provided as to be occlusive with respect toeach other, the present application being a division of my copendingapplication Ser. No. 89,540, filed Feb. 15, 1961.

In making the tubular bag material, the bag material is molded into along continuous tube, which is obtained by extruding from a conventionalextruder a synthetic resin under heated state upward through an annularextrusion gap to form continuously a tubular body in which are formed bymeans of incision-like molding grooves provided in a section of theannular extrusion gap simultaneously in the inner surface thereof raisedmale and female ribs parallel with the line of generation of the tubularbody. Then, in transporting this while clasped in a state of flatness bymeans of a pair of rolls provided at the top of the apparatus, air isfirst blown from the aforesaid molding mold into the tubular bag body tomaintain the same in a swelled state between the mold and the aforesaidrolls and by concurrently blowing in cold air uniformly from air inletpipes surrounding the tubular body against the tubular body maintainedin the swelled state the film is cooled uniformly. The tubular body isthen guided for engaging the occludent means.

The bag material which is now flat and maintaining its occluded statecan be finished into individual bags by cutting followed by sealing thecut edges. In actual practice, however, owing to the necessity ofaccomplishing printing of such as trademarks, trade names, etc. on thebag surface, the bag material that has been formed in a flat andcontinuous state, as described hereinabove, is first wound up on a reel,transferred to the printing step where after printing it is rewound onthe reel and thereafter cut and the cut edges simultaneously sealed.

The mode of practicing the invention will be described concretely belowwith reference to the accompanying drawings, in which:

FIG. 1 is a detailed front elevation of that section of a mechanismwhich continuously molds the bag material;

FIG. 2 is a top plan view of a mold section for making the bag material;

FIG. 3 is a cross-sectional view of the bag material taken along linesIII--III of FIG. 1;

FIG. 4 is a top plan view showing the bag material subsequent to itshaving been occluded;

FIG. 5 is a top plan view showing separate bags formed on a conveyorbelt after having been cut from the tube material and cross sealed;

FIG. 6 is an enlarged view in section of the resultant synthetic resinbag;

FIG. 7 is an enlarged view in section showing a modification of theoccluding ribs;

FIG. 8 is a cross-sectional view showing the bag material in which twosets of occluding ribs have been formed;

FIG. 9 is a descriptive drawing showing the above bag material in itsflattened form and the location where it is to be cut; and

FIG. 10 is an enlarged detailed fragmentary sectional view of theinterlocking occludent means.

As shown in FIGS. 1 and 2 an outer mold 1 has a core 3 with a shapednarrow annular extrusion gap 2 therebetween. Plastic is forced throughthe gap 2 by extruder mechanism not shown, and air introduced into atube extruded through the gap 2 through a pipe 4. As illustrated the gapis preferably of uniform width to form a tube of film of uniformthickness. There are formed molding grooves 7 and 8 in the outer surfaceof the core 3 communicating with the extrusion gap 2 for forming maleand female ribs 9 and 10 integrally with the bag body 6.

Directly above this mold (FIG. 1) there is provided a pair of deliveryrolls 11, 11 disposed in lateral fashion facing each other for claspingand delivering in a flat state the tubular bag body 6 that is extrudedfrom the mold. Air is blown in small amounts into the tubular bag body 6from the bottom through the aforesaid air inlet pipe 4, with the toppart of the bag body 6 being held together by means of the deliveryrolls 11, 11. The bag body 6 is swelled or inflated and maintained in atubular shape. Below the rolls 11, 11 there is provided a pair of guideplates 12, 12 facing each other in roof fashion whereby the shoulderportion of the bag body 6 swelled into a tubular shape is guided and isgradually pressed flat as shown in FIG. 1 and passes between the rolls11, 11.

At that part of the apparatus where the tubular bag body 6 ascends, acold air discharge section, not shown, is provided. Air is appropriatelysupplied and is blown against the outer surface of the bag body 6 toremove heat from the freshly molded film and thus cool the same.

The interlocking elements 9 and 10 are aligned and interlocked to holdthe opposed sides of tube material together. The bag body 6 is thusmolded into a flat belt-like shape. In actual practice, however, sincein most cases printing of such as trademarks, trade names, etc. areaccomplished, it is perhaps convenient to first wind up the bag materialin this state by guiding the same to a windup reel.

In the hereinabove-described apparatus, the cross-sectional shape of themale and female ribs suitable for occlusion of the bag body 6 can beobtained by suitably designing the configuration of the molding grooves7, 8. The cross-sectional shape of these male and female elements, 9, 10may be suitably determined in accordance with the uses to which the bagsare to be put. For example, as shown in FIG. 7, for a container to beused for fine powders the ribs may be so formed so that the labialsection of the female rib 9 is turned inward along the length of the ribwhile the male rib 10 is formed arrowhead shaped. In addition,regardless of the shapes of the male and female ribs, when two setsthereof are formed facing each other, as illustrated in FIG. 8, andsubsequently cut along line 0--0 midway between the two when the bagbody has been flattened as in FIG. 9, two bags are obtainable at thesame time. FIG. 10 shows the rib and groove elements 9 and 10 in greaterdetail. .Iadd.

Summarizing FIGS. 8 through 10, an elongated closed flexible integraltube of a flexible plastic film is shown at 6, with first and second ribelements shown at 10 at the upper and lower portion of FIG. 8, and firstand second groove elements shown at 9 at the upper and lower portion ofFIG. 8 respectively. The first rib and groove elements and second riband groove elements are complementary shaped and are positioned to becapable of being interlocked with the application of force to the outersurface of the tube at the element with the interlocked position shownin FIG. 9, and capable of being able to separate when forcibly drawnapart. The elements are spaced apart from each other in circumferentialdirections around the tube 6. The film includes the body forming sheetportions which are outside of the elements as shown laterally of theelements in FIG. 9 when the elements are interlocked, and the bodyforming sheet portion is at one side of each of the male elements, thatis, as viewed in FIG. 8, the body forming sheet portions are to the leftof the elements 10 as each is viewed in a direction looking radiallyinwardly of the tube. The film also includes flange forming sheetportions which are between the elements when interlocked as shown inFIG. 9 and which are at the other side of each of the male elementsrelative to the location of the body forming sheet portions. The flangeforming sheet portions may be subsequently separated axially along theirlength, such as along line 0--0 in FIG. 9, for providing a separateopening gripping flange for each of the rib and groove elements..Iaddend.

The incisions 7 and 8, which constitute a set of the molding grooves areincised in a part of the circumference of the core 3 with the shape ofthe grooves being of a wide variety. Since their positions will bedetermined by the size of the mold, by providing molding plates for thecore of the same size having a wide variety of incisions and selectivelyusing the same, it becomes possible to form ribs of any desired shape.

The bag body that has been molded as described hereinbefore is thenprocessed further in the following manner. First, the male and femaleribs that have been formed integrally in the bag body are occluded, thenafter flattening, to the surface of the bag body is imparted, ifrequired, the desired printing and thereafter by using an apparatus tobe described hereinafter the bag body is cut into the individual bag andsimultaneously therewith the cut edges of the bags are heat sealed.

In a position forward of a belt 203, rollers 207, 208 are disposedlongitudinally, around which an endless conveyor belt 209 is mounted.The tip of the bag body 6 which is delivered forth, FIG. 5, is made tobe transferred smoothly from the belt 203 to the radially moving part ofthe conveyor belt 209. The surface of this conveyor belt 209 by beingimparted a layer of such as, for example, silicon rubber is maintainedso that the bag body does not stick to the surface of the conveyor beltas a result of operations such as cutting and heat sealing. In addition,by suitable determination of the rotating speed of the rollers 207, 208,the rate of travel of the conveyor belt 209 is made to be greater thanthat of the bag body 6. An electro-thermic means is provided, whichmakes possible simultaneously with the cutting of the bag body the heatsealing of the cut edges. A pressure plate 226 is provided. Theindividual bags are severed and sealed as shown in the copendingapplication Serial 89,540. Further, at 237 is a set of superposed beltsthat have been provided forward of the conveyor belt 209 and have beenprovided for the purpose of removing the bags that have been conveyed bythe conveyor belt 209.

When the continuous tube is cut into predetermined widths starting atone end and the cut edges thereof are heat sealed, as a result of thefact that a unit width of a bag body leaves the bag body material and isplaced independently upon the top of the conveyor belt 209, the cutedges become spaced apart automatically from each other for an Sdistance.

In using these bags, by cutting the bags at the top f, FIG. 6, andopening up the engagement of the male and female ribs, the bag is readyto be filled with whatever it is to be filled with. After the bags arefilled the male and female ribs 9, 10 are again occluded, and ifnecessary, the mouth which was opened by cutting may be again sealedusing a heat sealer.

While the invention has been described with particular reference tospecific embodiments, it is to be understood that it is not to belimited thereto, but that changes may be made therein without departingfrom the scope of the invention which is defined in the appended claims.

Having thus set forth the nature of the invention, what is claimed is:.[.1. A structure for use in making a reclosable container comprising,providing a separate opening gripping flange for each element..].
 3. Incombination,an elongated closed flexible integral tube of a flexibleplastic film, first and second rib elements extending axially alongwithin said tube, first and second groove elements extending axiallyalong within said tube, said first rib and groove elements and saidsecond rib and groove elements being complementary shaped and positionedto be capable of being interlocked with the application of force to theouter surface of the tube at the element and to separate when forciblydrawn apart,said elements spaced apart from each other incircumferential directions, said film including body forming sheetportions positioned outside of elements when interlocked to be at oneside of each of the male elements for forming the bodies of bags formedfrom the tube, and said film including flange forming sheet portionsbeing between the elements when interlocked and being at the other sideof each of the male elements and which may be subsequently separatedaxially along their length for providing a separate opening grippingflange for each element. .[.4. A structure for use in making areclosable container comprising, an elongated flexible closed integraltube of a flexible plastic film, and first and second interlockingelements integral with the tube on the surface thereof shaped forcooperative pressure interengagement and for forcible separation, saidfirst interlocking element being arrowhead shaped in cross section andsaid second interlocking element being shaped to form a groove toembrace and interlock with said first element, said elements spacedapart from each other in both circumferential directions, said filmincluding a body forming a sheet portion between the interlockingelements at one side of the first element for forming the body of a bagformed from the tube, and said film including a flange forming sheetportion between the interlocking elements at the other side of saidfirst element which may be subsequently separated axially along itslength between the first and second elements for providing access to thebag formed from the tube and providing a separate opening grippingflange for each element..]. .[.5. A structure for use in making areclosable container comprising, an elongated flexible closed integraltube of a flexible plastic film, and first and second interlockingelements integral with the tube on the surface thereof shaped forcooperative pressure interengagement and for forcible separation, saidelements spaced apart from each other in both circumferentialdirections, said film including a body forming sheet portion between theinterlocking elements at one side of the first element for forming thebody of a bag formed from the tube, said film including a flange formingsheet portion between the interlocking elements at the other side ofsaid first element which may be subsequently separated axially along itslength between the first and second elements for providing access to thebag formed from the tube and providing a separate opening grippingflange for each element, and said flexible plastic film being ofsubstantially uniform thickness for said flange portion and said bodyportion..]. .[.6. A structure for use in making a reclosable container,comprising, an elongated flexible closed integral tube of a flexibleplastic film, and first and second interlocking elements integral withthe tube on the surface thereof shaped for cooperative pressureinterengagement and for forcible separation, said interlocking elementsbeing on the inner surface of said tube and projecting therefrom, saidelements spaced apart from each other in both circumferentialdirections, said film including a body forming sheet portion between theinterlocking elements at one side of the first element for forming thebody of a bag formed from the tube, and said film including a flangeforming sheet portion between the interlocking elements at the otherside of said first element which may be subsequently separated axiallyalong its length between the first and second elements for providingaccess to the bag formed from the tube and providing a separate openinggripping flange for each element..].
 7. A structure for use in making areclosable container in accordance with claim .[.20.]. .Iadd.3.Iaddend.wherein said first rib and groove elements and said second riband groove elements are interlocked holding the opposing sides of thetube together. .Iadd.
 8. A structure for use in making a reclosablecontainer in accordance with claim 3, wherein the first rib and grooveelements are opposing and are formed facing each other and interlockwhen the tube bag body has been flattened. .Iaddend..Iadd.
 9. Astructure for use in making a reclosable container in accordance withclaim 3, wherein the rib and groove elements are formed to face eachother within the tube so that with the tube bag body being flattened andcut between the elements two bags are obtainable at the same time..Iaddend.